Noctilucent CloudsOur connection with NASA's AIM spacecraft has been restored! New images from AIM show that the southern season for noctilucent clouds (NLCs) is underway. Come back to this spot every day to see AIM's "daily daisy," which reveals the dance of electric-blue NLCs around the Antarctic Circle..

GEOMAGNETIC UNREST POSSIBLE TODAY: Earth's magnetic field may be disturbed on Feb. 22nd by the glancing passage of a high-speed solar wind stream. The gaseous material is flowing from a southern hole in the sun's atmosphere, now facing our planet. Arctic sky watchers should be alert for auroras after local nightfall. Free:Aurora Alerts

SOLAR MINIMUM IS COMING: Today, for the 5th day in a row and the 23rd day so far this year, the face of the sun is blank. Take a close look at this image from NASA's Solar Dynamics Observatory. Can you find a sunspot?

(Answer: "No") The absence of sunspots heralds the approach of Solar Minimum. Sunspot numbers rise and fall with an ~11-year period, slowly oscillating between Solar Max and Solar Min. In 2018, the pendulum is swinging toward a deep minimum expected to reach nadir during the next 2 years.

THE ROBOTIC PETRI DISH: Spaceweather.com and the students of Earth to Sky Calculus routinely launch space weather balloons to monitor cosmic rays in the stratosphere. Lately we've been wondering, what else is up there? To answer that question, the students have built a robotic Petri Dish and launched it on a cosmic ray balloon payload. Play the video to see what happened:

During the 2.5 hour test flight, an onboard computer commanded the Petri Dish to open and close, over and over again. The servo motor and control computer worked flawlessly in the extreme cold of the stratosphere, reaching an altitude greater than 116,100 feet.

Now that we have tested the basic hardware of the Petri Dish, we plan to fly it again, this time with oils inside the dish to capture particles and microbes in the stratosphere. The Petri Dish can be commanded to open and close at any altitude, allowing us to control the altitude range of material we capture. We are also testing a "landing pad" that will protect the Petri Dish from touchdown collisions with rocks and other hard objects.

CROWD-FUNDING SPACE WEATHER RESEARCH: Did you know that cosmic rays in Earth's atmosphere are intensifying? It's true, and we are monitoring the phenomenon with regular space weather balloon flights to the stratosphere. This student science program is not supported by any government grant or corporate sponsorship. Instead, we raise our research funds by selling these:

On Dec. 31, 2017, the students of Earth to Sky Calculus flew a payload-full of these heart-shaped pendants to the stratosphere, 35.1 km (115,158 feet) above Earth's surface. They make great birthday and Mother's Day gifts.

You can have one for $119.95. Each glittering pendant comes with a greeting card showing the jewelry in flight and telling the story of its journey to the edge of space. Sales of this pendant support the Earth to Sky Calculus cosmic ray ballooning program and hands-on STEM research.

Every night, a network
of NASA
all-sky cameras scans the skies above the United
States for meteoritic fireballs. Automated software
maintained by NASA's Meteoroid Environment Office
calculates their orbits, velocity, penetration depth
in Earth's atmosphere and many other characteristics.
Daily results are presented here on Spaceweather.com.

On Feb. 21, 2018, the network reported 8 fireballs.(8 sporadics)

In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]

Near
Earth Asteroids

Potentially Hazardous Asteroids (PHAs)
are space rocks larger than approximately 100m that
can come closer to Earth than 0.05 AU. None of the
known PHAs is on a collision course with our planet,
although astronomers are finding new
ones all the time.

Notes: LD means
"Lunar Distance." 1 LD = 384,401 km, the distance
between Earth and the Moon. 1 LD also equals 0.00256
AU. MAG is the visual magnitude of the asteroid on
the date of closest approach.

Cosmic Rays in the Atmosphere

Readers, thank you for your patience while we continue to develop this new section of Spaceweather.com. We've been working to streamline our data reduction, allowing us to post results from balloon flights much more rapidly, and we have developed a new data product, shown here:

This plot displays radiation measurements not only in the stratosphere, but also at aviation altitudes. Dose rates are expessed as multiples of sea level. For instance, we see that boarding a plane that flies at 25,000 feet exposes passengers to dose rates ~10x higher than sea level. At 40,000 feet, the multiplier is closer to 50x. These measurements are made by our usual cosmic ray payload as it passes through aviation altitudes en route to the stratosphere over California.

What is this all about? Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly space weather balloons to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias and sudden cardiac death in the general population. Our latest measurements show that cosmic rays are intensifying, with an increase of more than 13% since 2015:

Why are cosmic rays intensifying? The main reason is the sun. Solar storm clouds such as coronal mass ejections (CMEs) sweep aside cosmic rays when they pass by Earth. During Solar Maximum, CMEs are abundant and cosmic rays are held at bay. Now, however, the solar cycle is swinging toward Solar Minimum, allowing cosmic rays to return. Another reason could be the weakening of Earth's magnetic field, which helps protect us from deep-space radiation.

The data points in the graph above correspond to the peak of the Reneger-Pfotzer maximum, which lies about 67,000 feet above central California. When cosmic rays crash into Earth's atmosphere, they produce a spray of secondary particles that is most intense at the entrance to the stratosphere. Physicists Eric Reneger and Georg Pfotzer discovered the maximum using balloons in the 1930s and it is what we are measuring today.